To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
SGA devices have been used successfully in patients of all ages in various clinical scenarios, including primary airway management under general anesthesia in the operating room, and resuscitation and emergent airway management in the emergency department (ED) and prehospital settings. SGA devices have been used as alternatives to face-mask ventilation and tracheal intubation by healthcare providers with proficient airway management skills, but also by those with less experience, to successfully oxygenate and ventilate the lungs. The clinical efficacy of SGA devices in children has been proven in a large number of clinical studies. Pediatric SGA devices have undergone an evolution in design since their introduction 30 years ago. These newer design features have improved the use of SGA devices to provide positive-pressure ventilation and facilitate fiberoptic-guided tracheal intubation. The evolution, versatility, and utility of the SGA device will be discussed in detail in this chapter.
Archaeobotanical studies tend to concentrate on the evidence for specialised agricultural food production, with less attention directed towards the use of plant foods within hunter-gatherer contexts. Here, the authors present evidence for the exploitation of Canarium nuts from four late hunter-gatherer sites in southern China. Canarium nuts contributed to the inhabitants’ diets from as early as 9000 cal BP. They also identify new uses of Canarium, c. 4500–4400 cal BP, as ritual offerings in the context of the introduction of rice and millet farming. The results are examined in the context of Canarium use across the wider Asia-Pacific region.
This paper discusses a detailed computational analysis that illustrated the influences of the magnetic field and external potential on the performance of a high-temperature Hall-effect electric thruster. Uniform and non-uniform magnetic field configurations were examined. The Lorentz force in the
direction, acting on the plasma, was shown to substantially enhance the flow velocity in the non-uniform magnetic field, which indicated that the non-uniform magnetic field was more suitable for Hall-effect electromagnetic acceleration. The static temperature increased with the external potential, especially near the region of cathode. This increment in gas temperature, together with the effect of the Lorentz force, results in the enhancement of the velocity at the front and back of the cathode. However, the Mach number and gas density decreased due to static temperature increases caused by the conversion of more electric power into internal energy. The thrust increased eventually with the increase of the average exit velocity.
Gust/turbulence–leading edge interaction is a significant source of airfoil broadband noise. An approach often used to predict the sound is based on Amiet’s flat-plate solution. Analytical studies have been conducted to investigate the influences of airfoil geometries, non-uniform mean flows and turbulence statistics, which, however, were often too convoluted. In this work, the problem is revisited by proposing simple corrections to the standard flat-plate solution to account for the effect of non-uniform mean flows of real airfoils. A key step in the method is to use a new space–time transformation that is analogous to the Prandtl–Glauert transformation to simplify the sound governing equation with spatially varying coefficients to a classical wave equation, which is then solved using the Schwarzschild technique as in Amiet’s solution. The impacts of Mach number, wavenumber and airfoil geometry on the prediction accuracy are investigated for both single-frequency and broadband cases, and the results are compared against high-fidelity simulations. It predicts the sound reduction by the airfoil thickness, and reveals that the reduction is caused by the non-uniform streamwise velocity. The limitations of the model are discussed and the approximation errors are estimated. In general, the prediction error increases with the airfoil thickness, the sound frequency and the flow Mach number. Nevertheless, in all cases studied in this work, the proposed correction can effectively improve the prediction accuracy of the flat-plate solution much more efficiently compared to numerical solutions of the Euler equations using computational aeroacoustics.
We incorporate deep learning (DL) into tiled aperture coherent beam combining (CBC) systems for the first time, to the best of our knowledge. By using a well-trained convolutional neural network DL model, which has been constructed at a non-focal-plane to avoid the data collision problem, the relative phase of each beamlet could be accurately estimated, and then the phase error in the CBC system could be compensated directly by a servo phase control system. The feasibility and extensibility of the phase control method have been demonstrated by simulating the coherent combining of different hexagonal arrays. This DL-based phase control method offers a new way of eliminating dynamic phase noise in tiled aperture CBC systems, and it could provide a valuable reference on alleviating the long-standing problem that the phase control bandwidth decreases as the number of array elements increases.
The Chinese National Twin Registry (CNTR), initiated in 2001, has now become the largest twin registry in Asia. From 2015 to 2018, the CNTR continued to receive Chinese government funding and had recruited 61,566 twin-pairs by 2019 to study twins discordant for specific exposures such as environmental factors, and twins discordant for disease outcomes or measures of morbidity. Omic data, including genetics, genomics, metabolomics, and proteomics, and gut microbiome will be tested. The integration of omics and digital technologies in public health will advance our understanding of precision public health. This review introduces the updates of the CNTR, including study design, sample size, biobank, zygosity assessment, advances in research and future systems epidemiologic research.
To reduce the operational complexity of the multipath estimating delay lock loop (MEDLL) and improve its anti-multipath performance for strobe correlators, a combination anti-multipath scheme, namely, the MEDLL on-strobe correlation technique, is proposed for global navigation satellite system (GNSS) signal processing. Short-delay multipath rays are separated from the strobe correlation function by the MEDLL mechanism; the dot product between the estimation residue and the standard correlation function or the BOC-PRN correlation function is then computed to eliminate the potential tracking ambiguity. Finally, this non-coherent combination result is sent to the loop filter to obtain anti-multipath code tracking. The proposed method is analysed via simulator data with a software receiver under different front-end bandwidth conditions. The results corroborate the better multipath mitigation capability and lower computational burden, although it is still difficult to eliminate all multipath interference, especially when the front-end bandwidth is insufficient.
Nanostructures are considered to have great potential and are widely used in energy storage and sensing devices, and atomic layer deposition (ALD) is of great help for better nanostructure fabrications. ALD can help to preserve the original properties of materials, and, meanwhile, the excellent film quality, nanoscale precise thickness control, and high conformality also play important role in fabrication process. To enhance the performance of energy storage and sensor devices, ALD has been used in directly fabricating active nanostructures, depositing protective passivation layers, etc. ALD is a convenient technique which has been widely engaged in energy-related fields including electrochemical conversion and storage, as well as in sensor and biosensors. The related research interest is increasing significantly. In this review, we summarize some of the latest works on ALD for batteries, supercapacitors, and sensors, and demonstrate the benefits of ALD comprehensively. In these devices, different materials are deposited by ALD under different conditions to achieve better battery performance, higher supercapacitor capacitance, and higher sensitivity. This review fully presents the strengths of ALD and its application in energy storage and sensing devices and proposes the future prospects for this rapidly developing technology.
Maintenance hemodialysis (MHD) is the use of a machine to filter wastes, salts and fluid from blood for at least 3 months to prolong the life of patients with advanced kidney failure. Although low dietary energy intake (DEI) has been observed in MHD patients, few studies have related DEI to the risk of mortality. To explore this relationship, a study included 1039 MHD patients from 8 centers was conducted. DEI was assessed by three 24-hour diet recalls including one dialysis day and two non-dialysis days, and was normalized to ideal body weight (IBW). All-cause mortality and CVD mortality were the primary and secondary outcomes, respectively. During a median follow-up of 28 months, all-cause and CVD mortality occurred in 230 (22.1%) and 140 (13.5%) participants. Overall, a U-shaped relationship was observed between DEI and all-cause or CVD mortality. The risk of all-cause mortality decreased significantly with the increase of DEI in participants with DEI <40kcal/kg IBW/d (HR, 0.98; 95% CI: 0.96-1.00) and increased significantly with the increase of DEI in those with DEI ≥40kcal/kg IBW/d (HR, 1.12; 95%CI: 1.04-1.20). Similarly, the risk of CVD mortality decreased with the increase of DEI in participants with DEI <36.5kcal/kg IBW/d (HR, 0.96; 95%CI: 0.93-0.99) and increased with the increase of DEI in participants with DEI ≥36.5kcal/kg IBW/d (HR, 1.11; 95%CI: 1.04-1.18). In summary, there was a U-shaped association between DEI and all-cause or CVD mortality, with a turning point at about 40 and 36.5 kcal/kg IBW/d, respectively, in MHD patients.
To assess the impact of a newly developed Central-Line Insertion Site Assessment (CLISA) score on the incidence of local inflammation or infection for CLABSI prevention.
A pre- and postintervention, quasi-experimental quality improvement study.
Setting and participants:
Adult inpatients with central venous catheters (CVCs) hospitalized in an intensive care unit or oncology ward at a large academic medical center.
We evaluated CLISA score impact on insertion site inflammation and infection (CLISA score of 2 or 3) incidence in the baseline period (June 2014–January 2015) and the intervention period (April 2015–October 2017) using interrupted times series and generalized linear mixed-effects multivariable analyses. These were run separately for days-to-line removal from identification of a CLISA score of 2 or 3. CLISA score interrater reliability and photo quiz results were evaluated.
Among 6,957 CVCs assessed 40,846 times, percentage of lines with CLISA score of 2 or 3 in the baseline and intervention periods decreased by 78.2% (from 22.0% to 4.7%), with a significant immediate decrease in the time-series analysis (P < .001). According to the multivariable regression, the intervention was associated with lower percentage of lines with a CLISA score of 2 or 3, after adjusting for age, gender, CVC body location, and hospital unit (odds ratio, 0.15; 95% confidence interval, 0.06–0.34; P < .001). According to the multivariate regression, days to removal of lines with CLISA score of 2 or 3 was 3.19 days faster after the intervention (P < .001). Also, line dwell time decreased 37.1% from a mean of 14 days (standard deviation [SD], 10.6) to 8.8 days (SD, 9.0) (P < .001). Device utilization ratios decreased 9% from 0.64 (SD, 0.08) to 0.58 (SD, 0.06) (P = .039).
The CLISA score creates a common language for assessing line infection risk and successfully promotes high compliance with best practices in timely line removal.
The authors report an unexpected anisotropy in tensile properties of a polycrystalline nickel-base superalloy after hot extrusion. The tensile strength of longitudinal specimens (parallel to extrusion direction) is 170–276 MPa higher than that of the transverse counterparts at the temperature ranging from 25 to 750°C. Microstructural investigation excludes possible causes leading to this phenomenon such as variation in the grain size, texture, and γ′ precipitates in two orientations. However, further transmission electron microscopy observation reveals that plenty of twins uniquely exist in longitudinal tensile samples after deformation which are probably responsible for the mechanical gap between the two orientations.
The effects of straw alone or combined with industrial and agricultural wastes as fertilizers on greenhouse gas (GHG) emissions are still poorly known in cropland areas. Here, we studied the effects of 3.5 Mg ha−1 straw and 3.5 Mg ha−1 straw combined with 8 Mg ha−1 of diverse wastes on GHG emission in a subtropical Jasminum sambac plantation in southeastern China. There were five treatments in a completely randomized block design: control, straw only, straw + biochar, straw + steel slag, and straw + gypsum slag. Emissions of carbon dioxide were generally higher in the treatments with waste than in the control or straw-only treatments, whereas the contrary pattern was observed in CH4 and N2O emission rates. Moreover, the total global warming potentials (GWPs) were no significantly higher in most of the amended treatments as compared to the control and straw-only treatments. In relation to the treatment with only straw, GWPs were 9.4% lower when steel slag was used. This finding could be a consequence of Fe amount added by steel slag, which would limit and inhibit the emissions of GHGs and their transport from soil to atmosphere. Our results showed that the application of slags did not increase the emission of GHGs and that the combination of straw with steel slag or biochar could be more effective than straw alone for controlling GHGs emission and improve soil C and nutrient provision.
Maternal supraphysiological estradiol (E2) environment during pregnancy leads to adverse perinatal outcomes. However, the influence of oocyte exposure to high E2 levels on perinatal outcomes remains unknown. Thus, a retrospective cohort study was conducted to explore the effect of high E2 level induced by controlled ovarian stimulation (COH) on further outcomes after frozen embryo transfer (FET). The study included all FET cycles (n = 10,581) between 2014 and 2017. All cycles were categorized into three groups according to the E2 level on the day of the human Chorionic Gonadotropin trigger. Odds ratios (ORs) and their confidence intervals (CIs) were calculated to evaluate the association between E2 level during COH and pregnancy outcomes and subsequent neonatal outcomes. From our findings, higher E2 level was associated with lower percentage of chemical pregnancy, clinical pregnancy, ongoing pregnancy, and live birth as well as increased frequency of early miscarriage. Preterm births were more common among singletons in women with higher E2 level during COH (aOR1 = 1.93, 95% CI: 1.22–3.06; aOR2 = 2.05, 95% CI: 1.33–3.06). Incidence of small for gestational age (SGA) was more common in both singletons (aOR1 = 2.01, 95% CI: 1.30–3.11; aOR2 = 2.51, 95% CI: 1.69–3.74) and multiples (aOR1 = 1.58, 95% CI: 1.03–2.45; aOR2 = 1.99, 95% CI: 1.05–3.84) among women with relatively higher E2 level. No association was found between high E2 level during COH and the percentage of macrosomia or large for gestational age. In summary, oocyte exposure to high E2 level during COH should be brought to our attention, since the pregnancy rate decreasing and the risk of preterm birth and SGA increasing following FET.
Micromalthidae is a small relictual family of archostematan beetles that is well known for its unusual asexual reproductive system characterised by parthenogenetic, viviparous, larviform females and sterile adults. Here we describe the first micromalthid beetle from mid-Cretaceous Burmese amber (ca.100Ma). Protomalthus burmaticus gen. et sp. nov. differs from all presently known micromalthid beetles by the presence of distinct frontoclypeal, labroclypeal, and medicranial sutures. The finding represents the first Mesozoic record of an adult micromalthid beetle and confirms a Gondwanan distribution of the family during the Cretaceous. A list of micromalthid beetles is provided, together with a key to extant and fossil species.